Chitosan based in situ forming polyelectrolyte complexes: A potential sustained drug delivery polymeric carrier for high dose drugs

Nanofibrous composite from chitosan-casein polyelectrolyte complex for rapid hemostasis in rat models in vivo

Bleeding causes ∼5.8 million deaths globally; half of the patients die if rapid hemostasis is not achieved. Here, we report a chitosan-casein (CC)-based nanofibrous polyelectrolyte complex (PEC) that could clot blood within 10 s in the rat femoral artery model in vivo. The nanofiber formation by self-assembly was also optimized for process parameters (concentration, mixing ratio, pH, and ultrasonication). Results showed that increasing the concentration of chitosan from 10 % to 90 % in the formulation increased the productivity (r = 0.99) of PECs but led to increased blood clotting time (r = 0.90) due to an increase in zeta potential (r = 0.98), fiber diameter (r = 0.93), and decreased surface porosity (r = -0.99), absorption capacity (r = -0.99). The pH also influenced the zeta potential of PEC, with an optimized pH of 8.0 ± 0.1 yielding clear nanofibers. Sonication improved the segregation of nanofibers by promoting water removal. The optimized PECs containing chitosan and casein in the ratio of 30:70 (CC30) at a pH of 8.0 and dehydration under sonication could clot the blood within 9 ± 2 s in vitro and 9 ± 2 s in rat femoral artery puncture model. The CC30 formulation did not cause any irritation or corrosion on rat skin. Histopathology and immunohistochemistry of various organs showed that CC30 was biocompatible and non-immunogenic under in vivo conditions.

Marine polysaccharides: Biological activities and applications in drug delivery systems

The ocean is the common home of a large number of marine organisms, including plants, animals, and microorganisms. Researchers can extract thousands of important bioactive components from the oceans and use them extensively to treat and prevent diseases. In contrast, marine polysaccharide macromolecules such as alginate, carrageenan, Laminarin, fucoidan, chitosan, and hyaluronic acid have excellent physicochemical properties, good biocompatibility, and high bioactivity, which ensures their wide applications and strong therapeutic potentials in drug delivery. Drug delivery systems (DDS) based on marine polysaccharides and modified marine polysaccharide molecules have emerged as an innovative technology for controlling drug distribution on temporal, spatial, and dosage scales. They can detect and respond to external stimuli such as pH, temperature, and electric fields. These properties have led to their wide application in the design of novel drug delivery systems such as hydrogels, polymeric micelles, liposomes, microneedles, microspheres, etc. In addition, marine polysaccharide-based DDS not only have smart response properties but also can combine with the unique biological properties of the marine polysaccharide base to exert synergistic therapeutic effects. The biological activities of marine polysaccharides and the design of marine polysaccharide-based DDS are reviewed. Marine polysaccharide-based responsive DDS are expected to provide new strategies and solutions for disease treatment.

Evaluation of chitosan/xanthan gum polyelectrolyte complexes potential for pH-dependent oral delivery of escin

Escin is an amphiphilic and weakly acidic drug that oral administration may lead to the irritation of gastric mucosa. The entrapment of escin into chitosan (CH)/xanthan gum (XG)-based polyelectrolyte complexes (PECs) can facilitate controlled drug release which may be beneficial for the reduction of its side effects. This study aimed to investigate the influence of escin content and drying method on the formation, physicochemical, and controlled, pH-dependent drug release properties of CH/XG-based PECs. Measurements of transmittance, conductivity, and rheological characterization confirmed the formation of CH/XG-based PECs with escin entrapped at escin-to-polymers mass ratios 1:1, 1:2, and 1:4. Ambient-dried PECs had higher yield, entrapment efficiency, and escin content in comparison with spray-dried ones. FT-IR spectra confirmed the interactions between CH, XG, and escin, which were stronger in ambient-dried PECs. PXRD and DSC analyses showed the amorphous escin character in all dry PECs, regardless of the drying method. The most promising controlled and pH-dependent in vitro escin release was from the ambient-dried PEC at the escin-to-polymers mass ratio of 1:1. For that reason and due to the highest yield and entrapment efficiency, this carrier has the potential to prevent the irritation of gastric mucosa after oral administration of escin.

Weak Polyelectrolytes as Nanoarchitectonic Design Tools for Functional Materials: A Review of Recent Achievements

The ionization degree, charge density, and conformation of weak polyelectrolytes can be adjusted through adjusting the pH and ionic strength stimuli. Such polymers thus offer a range of reversible interactions, including electrostatic complexation, H-bonding, and hydrophobic interactions, which position weak polyelectrolytes as key nano-units for the design of dynamic systems with precise structures, compositions, and responses to stimuli. The purpose of this review article is to discuss recent examples of nanoarchitectonic systems and applications that use weak polyelectrolytes as smart components. Surface platforms (electrodeposited films, brushes), multilayers (coatings and capsules), processed polyelectrolyte complexes (gels and membranes), and pharmaceutical vectors from both synthetic or natural-type weak polyelectrolytes are discussed. Finally, the increasing significance of block copolymers with weak polyion blocks is discussed with respect to the design of nanovectors by micellization and film/membrane nanopatterning via phase separation.

A Review of Gum Hydrocolloid Polyelectrolyte Complexes (PEC) for Biomedical Applications: Their Properties and Drug Delivery Studies

The utilization of natural gum polysaccharides as the vehicle for drug delivery systems and other biomedical applications has increased in recent decades. Their biocompatibility, biodegradability, and price are much cheaper than other materials. It is also renewable and available in massive amounts, which are the main reasons for its use in pharmaceutical applications. Gum can be easily functionalized with other natural polymers to enhance their applications. Various aspects of the utilization of natural gums in the forms of polyelectrolyte complexes (PECs) for drug delivery systems are discussed in this review. The application of different mathematical models were used to represent the drug release mechanisms from PECs; these models include a zero-order equation, first-order equation, Higuchi, simplified Higuchi, Korsmeyer–Peppas, and Peppas–Sahlin.

Preparation and Characterization of Aminoglycoside-Loaded Chitosan/Tripolyphosphate/Alginate Microspheres against E. coli

Although aminoglycosides are one of the common classes of antibiotics that have been widely used for treating infections caused by pathogenic bacteria, the evolution of bacterial resistance mechanisms and their inherent toxicity have diminished their applicability. Biocompatible carrier systems can help sustain and control the delivery of antibacterial compounds while reducing the chances of antibacterial resistance or accumulation in unwanted tissues. In this study, novel chitosan gel beads were synthesized by a double ionic co-crosslinking mechanism. Tripolyphosphate and alginate, a polysaccharide obtained from marine brown algae, were employed as ionic cross-linkers to prepare the chitosan-based networks of gel beads. The in vitro release of streptomycin and kanamycin A was bimodal; an initial burst release was observed followed by a diffusion mediated sustained release, based on a Fickian diffusion mechanism. Finally, in terms of antibacterial properties, the particles resulted in growth inhibition of Gram-negative (E. coli) bacteria.

Study of Different Chitosan/Sodium Carboxymethyl Cellulose Proportions in the Development of Polyelectrolyte Complexes for the Sustained Release of Clarithromycin from Matrix Tablets

This study investigated the combination of different proportions of cationic chitosan and anionic carboxymethyl cellulose (CMC) for the development of polyelectrolyte complexes to be used as a carrier in a sustained-release system. Analysis via scanning electron microscopy (SEM) Fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), and powder X-ray diffraction (PXRD) confirmed ionic interactions occur between the chitosan and carboxymethyl cellulose chains, which increases drug entrapment. The results of the dissolution study in acetate buffer (pH 4.2) showed significant increases in the kinetic profiles of clarithromycin for low proportions of chitosan/carboxymethyl cellulose tablets, while the tablets containing only chitosan had high relaxation of chitosan chains and disintegrated rapidly. The Korsmeyer–Peppas kinetic model for the different interpolymer complexes demonstrated that the clarithromycin transport mechanism was controlled by Fickian diffusion. These results suggest that the matrix tablets with different proportions of chitosan/carboxymethyl cellulose enhanced the ionic interaction and enabled the prolonged release of clarithromycin.

Ghatti gum-base graft copolymer: a plausible platform for pH-controlled delivery of antidiabetic drugs

In the present study, we aimed to develop a novel pH-sensitive polymeric delivery system (GG-g-PMMA) for antidiabetic therapy via grafting ghatti gum (GG) with methyl methacrylate (MMA) chains. The free radical polymerization technique was adopted to graft ghatti gum with methyl methacrylate, using ceric ammonium nitrate (CAN) as a redox initiator. The impact on grafting parameters such as grafting percentage (G%) and grafting efficiency (GE), of monomer and initiator concentrations was evaluated. The batch with higher grafting efficiency and percentage grafting was selected and characterized by elemental analysis (C, H and N), DSC, FT-IR spectroscopy, XRD, 1H-NMR and SEM morphology study. In addition, the efficacy of GG-g-PMMA-based pellets loaded with the hypoglycemic agent, metformin hydrochloride, to sustain drug release was investigated. In vitro release studies demonstrated a pH-dependent sustained release of the drug from GG-g-PMMA pellets. In addition, acute oral toxicity studies and histopathological analysis suggested the safety and biocompatibility of the grafted gum. Most importantly, in vivo efficacy studies underscored the efficient hypoglycemic potential of the prepared formulation, which was comparable to that of a sustained release marketed formulation. These results suggest that the developed pH-sensitive polymeric delivery system (GG-g-PMMA) might represent a promising delivery vehicle for facilitated antidiabetic therapy.

Efficient Prediction of In Vitro Piroxicam Release and Diffusion From Topical Films Based on Biopolymers Using Deep Learning Models and Generative Adversarial Networks

The purpose of this study was to simultaneously predict the drug release and skin permeation of Piroxicam (PX) topical films based on Chitosan (CTS), Xanthan gum (XG) and its Carboxymethyl derivatives (CMXs) as matrix systems. These films were prepared by the solvent casting method, using Tween 80 (T80) as a permeation enhancer. All of the prepared films were assessed for their physicochemical parameters, their in vitro drug release and ex vivo skin permeation studies. Moreover, deep learning models and machine learning models were applied to predict the drug release and permeation rates. The results indicated that all of the films exhibited good consistency and physicochemical properties. Furthermore, it was noticed that when T80 was used in the optimal formulation (F8) based on CTS-CMX3, a satisfactory drug release pattern was found where 99.97% of PX was released and an amount of 1.18 mg/cm² was permeated after 48 h. Moreover, Generative Adversarial Network (GAN) efficiently enhanced the performance of deep learning models and DNN was chosen as the best predictive approach with MSE values equal to 0.00098 and 0.00182 for the drug release and permeation kinetics, respectively. DNN precisely predicted PX dissolution profiles with f₂ values equal to 99.99 for all the formulations.

Connecting the dots in drug delivery: A tour d'horizon of chitosan-based nanocarriers system

One of the most promising pharmaceutical research areas is developing advanced delivery systems for controlled and sustained drug release. The drug delivery system (DDS) can be designed to strengthen the pharmacological and therapeutic characteristics of different medicines. Natural polymers have resolved numerous commencing hurdles, which hindered the clinical implementation of traditional DDS. The naturally derived polymers furnish various advantages such as biodegradability, biocompatibility, inexpensiveness, easy availability, and biologically identifiable moieties, which endorse cellular activity in contrast to synthetic polymers. Among them, chitosan has recently been in the spotlight for devising safe and efficient DDSs due to its superior properties such as minimal toxicity, bio-adhesion, stability, biodegradability, and biocompatibility. The primary amino group in chitosan shows exceptional qualities such as the rate of drug release, anti-microbial properties, the ability to cross-link with various polymers, and macrophage activation. This review intends to provide a glimpse into different practical utilization of chitosan as a drug carrier. The first segment of the review will give cognizance into the source of extraction and chitosan's remarkable properties. Further, we have endeavored to provide recent literature pertaining to chitosan applications in various drug delivery systems via different administration routes along with current patented chitosan formulations.

Functional Chitosan-based Materials for Biological Applications

Background:

Bio-based materials, as the plentiful and renewable resources for natural constituents which are essential for biomedical and pharmaceutical applications, have not been exploited adequately yet. Chitosan is a naturally occurring polysaccharide obtained from chitin, which has recently attracted widespread attention owing to its excellent activity. This review shows the methods of extraction and modification of chitosan and provides recent progress of synthesis and use of chitosan-based materials in biological applications.

Methods:

By consulting the research literature of the last decade, the recent progresses of functional chitosan-based materials for biological applications were summarized and divided into the methods of extraction chitosan, the chemical modification of chitosan, chitosan-based materials for biological applications were described and discussed.

Results:

Chemical modification of chitosan broadens its applications, leading to developing numerous forms of chitosan-based materials with excellent properties. The excellent bioactivity of chitosan-based material enables it serves potential applications in biomedical fields.

Conclusion:

Chitosan-based materials not only exhibit the excellent activities of chitosan but also show other appealing performance of combined materials, even give the good synergistic properties of chitosan and its composite materials. Further studies are needed to define the ideal physicochemical properties of chitosan for each type of biomedical applications. The development of various functional chitosan-based materials for biological applications will be an important field of research, and this kind of material has important commercial value.

Self-stabilized chitosan and its complexes with carboxymethyl starch as excipients in drug delivery

This study focuses on the behavior of chitosan (CHI) and its polyelectrolyte complexes with carboxymethyl starch (CMS) used as monolithic matrices with acetaminophen as drug tracer. Two different chitosan grades were tested alone or associated in various ratios with CMS as excipients for tablets obtained by direct compression. The degree of deacetylation (DDA) of CHI, estimated from 1H NMR and FTIR data, was correlated with X-ray diffraction and scanning electron microscopy (SEM) to evaluate structural organization of the monolithic matrices. In vitro drug dissolution assays showed major differences in CHI kinetic profiles between tablets exposed to acidic medium for 2h (to mimick gastric passage) prior to dissolution in simulated intestinal fluid (SIF), and those administered directly to SIF. Prior exposure to acidic SGF conducted to longer dissolution profiles (release completed after 16 h) and preservation of tablet shape, whereas tablets directly incubated in SIF were rapidly disintegrated. The improved properties of chitosan matrices exposed to SGF may be related to an outer compact coating layer (visible in SEM). The effect of self-stabilization of chitosan in acidic medium was compared to that due to formation of polyelectrolyte complexes (PEC) in co-processed polymeric systems (CHI:CMS). The self-formed membrane following exposure to gastric acidity appears to help maintaining tablet integrity and allows higher drug loading, recommending CHI and its complexes with CMS as excipients for drug delivery.

Zinc-Modified Nanotransporter of Doxorubicin for Targeted Prostate Cancer Delivery

This work investigated the preparation of chitosan nanoparticles used as carriers for doxorubicin for targeted cancer delivery. Prepared nanocarriers were stabilized and functionalized via zinc ions incorporated into the chitosan nanoparticle backbone. We took the advantage of high expression of sarcosine in the prostate cancer cells. The prostate cancer targeting was mediated by the AntiSar antibodies decorated surface of the nanocage. Formation of the chitosan nanoparticles was determined using a ninhydrin assay and differential pulse voltammetry. Obtained results showed the strong effect of tripolyphosphine on the nanoparticle formation. The zinc ions affected strong chitosan backbone coiling both in inner and outer chitosan nanoparticle structure. Zinc electrochemical signal depended on the level of the complex formation and the potential shift from -960 to -950 mV. Formed complex is suitable for doxorubicin delivery. It was observed the 20% entrapment efficiency of doxorubicin and strong dependence of drug release after 120 min in the blood environment. The functionality of the designed nanotransporter was proven. The purposed determination showed linear dependence in the concentration range of Anti-sarcosine IgG labeled gold nanoparticles from 0 to 1000 µg/mL and the regression equation was found to be y = 3.8x - 66.7 and R² = 0.99. Performed ELISA confirmed the ability of Anti-sarcosine IgG labeled chitosan nanoparticles with loaded doxorubicin to bind to the sarcosine molecule. Observed hemolytic activity of the nanotransporter was 40%. Inhibition activity of our proposed nanotransporter was evaluated to be 0% on the experimental model of S. cerevisiae. Anti-sarcosine IgG labeled chitosan nanoparticles, with loaded doxorubicin stabilized by Zn ions, are a perspective type of nanocarrier for targeted drug therapy managed by specific interaction with sarcosine and metallothionein for prostate cancer.